


Regret

by uostiji_iaK



Category: IDOLiSH7 (Video Game)
Genre: Adpoted, Angst, Chronic Illness, Cold Riku, Gen, Idols, Minor Character Death, Tenn regreting his decision, Twins, missunderstandings, slight angst
Language: English
Status: In-Progress
Published: 2020-12-25
Updated: 2020-12-27
Packaged: 2021-03-10 18:54:41
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 4,127
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28321965
Author URL: https://archiveofourown.org/users/uostiji_iaK/pseuds/uostiji_iaK
Summary: Nanase Tenn made a decision.Nanase Riku suffered the consequences of it.When they reunite, it doesn't go as Tenn thought.
Relationships: ALL PLATONIC, IDOLiSH7 & Nanase Riku, Kujou Ten & Nanase Riku
Comments: 1
Kudos: 35





	1. Decision and Reunion

**Author's Note:**

> In this AU Tenn regretted the decision he made as soon as he left. Riku treats him coldly, as he suffered the consequences of that decision. Tenn doesn't know about anything that happened after he left, Riku was adopted by his uncle from their dad's side, all characters from that family aren't my OCS, they're just random characters I thought of.

"Tenn-nii!" a young red haired child yelled out, on the verge of teras. The other boy didn't turn around, he kept walking, his white hair moving with the wind.

"I'm going with him, Riku" he spoke, to the child trembling behind him as he entered the car with a strange man. The red head dropped to the floor, clutching his chest from the pain, his breathing became frantic and coughs escaped his mouth as he called out to his brother, crying his eyes out.

The white haired boy, watched in horror through the car window, as his younger twin brother collapsed to the floor, but it was too late, he already made a decision. He could only watch as their parents ran out of the house and panicked at the sight of the red head child collapsed on the floor, as the car started moving, he only cought a glance of the red haired man taking out his phone as the white haired woman cried hugging her child.

"You made a decision Tenn, don't look back" the man said to the child who looked back at the cars back window as the moved further and further.

\------

Kujo Tenn, a young idol, from the new idol group TRIGGER. He was the modern day angel and the perfect center. He made a decision, he chose the life without his family. He regreted that decision.

\------

A red haired child sat in the hospital corridor, with him there was no one.

"I'm sorry for your loss, Riku-kun" the word of the doctor before him still didnt register in his mind.

Over the course of less than 2 years, the 14 year old became not only an only child, but now an orphan.

Loosing his mother a few months ago to a traffic accident and now his father to the same illness he had, while his only sibling threw him away. Nanase Riku was all alone in the world now.

He was sad, but he couldn't cry. He bacame used to loosing people he loved.

As he sat in the corridor, a woman who just arrived approached him. "Riku-kun" she called out to him, finally snapping him out of his thoughts.  
"I'll be your guardian along side my husband, your uncle, Eiji. My name is Haru Nanase."

With that Riku now had a home again. The new family cared for him, finally adopting him as their own before his 17th birthday. His surname didn't change, as it was his dads brother's family. He was once again a happy child, with 2 older siblings, a sister and a brother, with 2 twin boys as younger brothers. They accepted him.

\------

Riku was now 18 years old, he was scouted by Takanashi productions at a karaoke bar, he visited with his friends once after school.

He soon found himself in a practice room, playing basketball with others who were scouted around the same time.

His cheerful personality made him become friends with others quickly, and before he knew it, he became their center.

Now as Idolish7, they were preparing for their first official live, everyone was excited more and more as the date neared. Their street performances earned them a few fans and were fun for the group.

And that story brings us to today.

A week after the live, Idolish7 accepted their first appearance at a TV show. They were all excited, it was their first job after all. Exept they weren't told one small detail about the job, one other idol group was also invited to the show, TRIGGER.

\------

Idolish7 was currently changing clothes, for the show, they were to appear as idols after all, they had to wear their stage clothes. Riku was still a bit embarrassed, walking around in his stage clothes that exposed his chest, but the excitement was stronger than his embarrassment.

They were soon called into the studio, to start the rehearsal for the recording that was scheduled an hour later.

As the song started and Idolish7 was dancing on the set, TRIGGER was called to stand by for their rehearsal.

Tenn was never intrested in other idol groups, but that all changed when he walked into the studio that day.

He froze in his step, as he heard the voice in the studio. His eyes were fixed on a certain red head, who was currently dancing, with a wide grin on his face alongside 6 other people. His happiness shining brightly made everyone in the studio smile too.

_"tenn-nii, i want to make others smile!" a 7 year old said grinning._

As idolish7 finished, his gaze was still fixed on Riku. The red head noticed the gaze and turned towards the source of it. As soon as their eyes met, the happiness in his beautiful red eyes disappeared and was replaced with surprise, sadness, but what tenn felt the most from that gaze was disgust.

"Riku" the white haired teen spoke without thinking, his expression was now a mix of worry, surprise and happiness. He walked up to the red head that was now looking at him. "You're Riku, right?!" His eyes were almost crying.

The read head only starred at him, his expression unchanged.

"Yes, that is my name, Kujo-san" his eyes as cold as ever, even idolish7 was surprised by this sight. Their cheerful center was giving someone a cold shoulder.

"I knew it" Tenn smiled, with watery eyes. "I missed you" he said to the boy before him. He finally reunited with his younger twin brother, whom he regretted leaving.

"Is that so." This cold reply surprised Tenn, he was happy to meed the person he missed the most, but it didnt seem like his feelings were returned.

"Riku, do you know him?" Mitsuki pitched in, as he approached the red haired boy.

"I'm his brother" Tenn said without giving riku a chance to reply.

"Really? You never told us you had more siblings Riku" this time it was Yamato who joined in.

"I don't." This sentence that escaped the read heads mouth, shattered tenn.

"I only have my 2 older siblings and my twin younger brothers." Riku continued. Tenn couldn't believe what he just heard. He was his only sibling.

"Riku, I'm your only brother." Tenn said not believing ehat he just heard. "We're twins aren't we?!" he raised his voice.

"Yes, we were twins" Riku confirmed, "But we aren't brothers." he said coldly as he looked at Tenn, who now took a step back.

"What do you mean Riku?" Tenn questioned him, his eyes now widened in surprise.

"We have different families dont we?" Riku smiled slightly when he said that, "We aren't siblings, dont you know that? After you left, i gained a new family." Riku said proudly, but Tenn was shocked by that.

"what do you mean?" he questioned.   
"what happened?"

 _"So you don't even know that. Aren't you cruel?"_ Riku said playfully, "I'm not going to tell you that now. Kujo-san" The emphasis on his last name saddened Tenn. He was no longer called Tenn-nii by Riku.

"what do you-" Tenn started, "TRIGGER please start your rehearsal." he was interrupted by the staff, who were now ready for their rehearsal.

Tenn had no choice, he had to postpone this conversation.

\------

The show that night went smoothly, the two idol groups has a quick joint interview on the show, prior to their performances. Right now the two idol groups went back to the other studio, where they would sing their songs. This time there were chairs provided for TRIGGER as Idolish7 performed first.

Riku didn't talk to Tenn, it almost seemed like he avoided him. Right now Tenn was sitting on his chair next to Gaku and Ryu who were playing with their phones. His gaze fixed on Riku, who was now laughing with his friends as the stood on the set, waiting for a signal from the filming crew to get on their spots. Riku seemed unaffected by their exchange ealier, he became cheerful again. He watched as Riku fooled around with Nagi, earning them a small nagging from Iori, as the 4 remaing members lauged at them. Riku was happy without him.

As the director signaled to get on standby, Idolish7 quickly scrambled to their position, seemingly tripping one on another.

As soon as they hear the staff count down from 5 to 1, they all piped down, standing motionless on their positions. And as soon as music of their song "Monster Generation" started playing, Riku beamed with his usual smile as he danced and sang, the others following fit with him, with wide smiles on their faces. Even Gaku and Ryu smiled as they watched the younger group.

"Thank you very much" the staff clapped and thanked the idols after their performance was done. Idolish7 also thanked the staff, but thier cheerfulness was now not as prominent as before. As soon as they came off the set, Iori supported Riku as they all hurried to leave the room. As they went past TRIGGER, Tenns eyes widened as he saw Riku was breathing heavily with a pained expression on his face. Idolish7 nodded as they passed them, hurriedly going to their prep room.

TRIGGER could only watch them leave through the door, before their attention was taken by the director telling them to stand by. Tenn put on his stern expression, his feelings didnt matter now. He's a professional.

\------

After the performance TRIGGER shuffled in their prep room, it was the last schedule for them, as it was already evening, so each of them wanted to leave for home as soon as they could to get some rest.

Tenn was the last one to exist the building, he tried to find Riku after changing but Idolish7 wasn't in their prep room any more.

As he exited the building he saw Riku sitting on a bench in front of the building, but before he could call out to him, two elementary schoolers approached the red head.

"Riku-nii!" Both boys called out, as the read head turned to them, just before they collided their brother in a hug.

Tenn widened his eyes at the statement.

"Havent seen you two in a while, Abe, Natsu." Riku said while whe returned the hug of the children. "Why are you here alone though." he asked the two after they let go of him.

"We arent alone." Natsu replied "Nee-chan is with us! We ran ahead of her" abe finished.

"Yui-nee?" Riku asked the twins before him. Ten was surprised Riku called someone other than him like an older sibling.

Before the twins could answer him, Riku noticed Tenn was looking at him, again.

"Do you need something?" he asked as he straightened himself up, the two children were surprised as Tenn approached them.

"who is he, Riku-nii?" the boys asked the read head.

"This is Kujo Tenn-san" The red head replied, "He used to be my older twin brother." he continued as he looked at Tenn coldly.

"You're also a twin, Riku-nii?" One of the boys asked, surprised by the sentence.

"Yep, although we aren't identical like you two." Riku smiled as he ruffled the younger boys hair, earning a laugh from the boy.

"Who are they, Riku." Tenn finally asked, he just watched the interaction between them without being able to say a word.

Riku looked at Tenn, his eyes weren't as cold as ealier,but they still weren't welcoming.

"Those are my younger brothers, Abe and Natsu, they're twins like us, just identical ones." Riku explained.

"Younger... Siblings..." Tenn couldn't process this, the children looked to be around the age of elementary schoolers, there's no way he wouldn't know about them if they were their siblings. He would definitely remember having more siblings.

"Yeah, but they aren't your siblings." Riku looked at tenn, this confused the white head even more. "They're from my adopted family."

This shocked Tenn even more than the children before him. Adopted family, what was Riku talking about.

"Adopted? How come?" Tenn questioned.

"I was adopted." Riku dropped a bomb on Tenn.

"How... Where are our parents then?!" Tenn raised his voice, he didn't understand anything anymore. What happened in the 6 years he was gone.

"You don't know?" Riku raised his eyebrows, he thought Tenn knew all along. "Mom died in a traffic accident a few weeks after you left and our Father, he lost to his illness." Riku replied, not looking away from Tenn.

Tenn was now even more confused. Why didn't he know. _He should have been informed about this by Kujo. Why wasn't he._ Several questions passed his mind, but before he could say anything else, a blonde hair woman appeared in the view of his eyes, the two boys immediately let go of Rikus hands and ran to her, calling out 'Nee-chan' to her.

"Riku!" the woman called out as she stopped next to the read head, she was a bit shorter than Riku. Her red eyes were a similar color to Rikus. "are you done with work already?" She asked.

"Ah yes, I was waiting for you, Yui-nee" he replied shifting his attention to her. Tenn stood there as he watched the conversation between the 4, he recognized the woman, but it didn't click until she talked to him.

"Tenn-kun. Long time no see!" she smiled at the other boy. "Mom and Dad haven't seen you in a while, you should visit us someday, you know"

_He finally realized, this was their cousin._

"Yui-nee he's busy" Riku replied before Tenn even processed the conversation. Riku took the hands of the two boys again. "Besides, we aren't family anymore, remember? We should get going, I want to spend some time with Mom and Dad today too, I'm only visiting till tomorrow, so lets go." Riku flased a smile at the girl.

"Ah, its already getting late too." she sighed, "Let's get going then." She started walking after the boys. Riku didn't even say goodbye to Tenn, as he quickly got pulled by the twins, who were excited by the aspect of their brother finally coming home.

Before the girl left, she stopped and turned back to Tenn." You should visit us sometime, despite what Riku said." she smiled. "Your aunt and Uncle adopted Riku 4 years ago, they would be happy to see you too, I'm sure!" she said and then waved goodbye before running after the 3 boys.

Tenn was left alone and confused. _Their aunt and uncle? Their cousin being Called One-chan by Riku? Two younger boys, who were apparently twins, calling Riku nii? Their parents were dead?_ What the hell happened in the 6 years he wasn't there.

As Tenn was processing the information he aquired that day, Gaku called out to him from the car. Anesagi, their manager, was driving them home today.

"How long are we supposed to wait for you, brat. I want to go home too, you know." Gaku said, clearly annoyed, but to his surprise Tenn didn't insult him back. The white head just quietly got into the car, closing the door behind himself.

Tenn felt like he didn't know anything anymore.


	2. Hurt and Happy

**Notes for the Chapter:**

> I'm sorry for a mistake I made, Natsu and Abe are elementary schoolers! not middle schoolers, they're 8. When Tenn left the family they were almost 2 years old, their parents didn't keep a close relationship with that side of the Nanase family, hence why Tenn didn't know about them, even as cousins.

Ten laid in his bed, today was way too eventful for him. A reunion with a person he missed the most, learning his parents died, his brother now had another family and was an idol as well. He didn't know what to process first and to what he should react.

As he stared at the ceiling of his room, he started crying. Reason? He was abandoned by the person he abandoned. He finally felt what Riku did that day he left. Sadness, loneliness, surprise and slight anger.

Tenn laid there crying until he fell asleep, his emotions were as confused as he was. He shouldn't have left that day, or ever. He left Riku, who later on lost his leftover family. He left his own brother to be alone in this world. He felt horrible.

The next day, Ryu and Gaku could tell Tenn was out of it. He came with his hair still messy as if he just woke up, his mood was the worst they've seen and he was missing steps in practice. Tenn the perfectionist was a mess. Was the world ending finally?

All came to mind to the two, was yesterday's performance on that evening show. They watched as their center interacted with another idol, yelling that they were brothers and twins, while the other looked a bit offended by Tenn's words.

They wanted to question him yesterday, but he didn't react to anything. They saw him talk to that guy once more as they waited in the car, and when they finally took off, they saw the group of that teen walking happily together, while Tenn looked at them through the car window with a sad expression.

"Tenn, are you alright?" Ryu was the first one to speak up, as Gaku was lost in his thoughts. Besides, Ryu had a batter chance of getting any information out of him.

"Yes, I'm fine" Tenn turned to look at Ryu, with his water bottle in hand, as he was just drinking it.

"Ya sure?" This time it was Gaku who joined in, Tenn stared at the two for a short while before he started crying. This sight surprised both of them, after all they never saw him cry.

"No, I'm not alright" Tenn said as his tears streamed down his face, "I finally met my twin brother, just to find out he was adopted and our parents died." Tenn said in between sobs. "It hurts. It hurts being abandoned."

"Tenn how about we sit down, alright?" Ryu tried to calm the white head, "You can tell us the whole thing if that'll make you feel better, alright? We will listen to you."

Gaku followed the two of them to the other side of the room, there was a bench there where they could sit.

"I'm just so confused about everything." Ten started as he sat down.

"How about you start with how this all happened" Gaku said to Tenn, it was unusual for him to be nice and gentle to the white head, but as the teen had a mental breakdown right in front of them, Gaku didn't want to make this worse.

"alright." Tenn said as he wiped his face from tears. "As I said, I have a twin brother. A younger twin brother."

"So you were serious about this. But how come your brothers but your surnames are different." Ryu questioned.

"I left home at 12 years old with Kujo to become an idol." Tenn said looking down onto the floor. "I regretted that decision as soon as I made it." he said quietly.

"So your surname was originally Nanase?" This time it was Gaku who tried to keep the conversation going.

"Yes. Although I was erased from the family register, so I'm no longer a part of the Nanase family." this reply didn't shock them as much, if he was adopted he wouldn't be on the family registration of the family he left.

"I met Riku, my brother yesterday in the studio. He's the center of the group, Idolish7, if I remember right." Tenn explained further. "I was so happy I met him, but I could feel he wasn't. I felt disgust from him when he looked at me with his eyes, they weren't even one bit welcoming." 

Tenn then told them about the meeting with the twins who called Riku nii, and their cousin who was called nee, that he learned of their parents death and that Riku got adopted by a relative from the Nanase family.

He wasn't informed about any of this by Kujo, who promised that he would if anything major happened. But Kujo never did that. Tenn left Riku all alone in the world.

_**\------** _

"Riku, come to the table, breakfast is ready!" a woman with blonde hair and blue eyes yelled into the corridor of a 2-story house from the kitchen.

After a few seconds, sounds of some coming down the stairs could be heard, and a certain red head appeared in the kitchen.

" Let me help you, mom" Riku said as he took some cups from the cabinet and started pouring tea into them.

"Thank you, can you go get Abe and Natsu after you're done? They still aren't up" the woman sighed. The twins were very bad at waking up in the morning, they always woke up late.

"Sure." he replied, although he knew that it wouldn't be easy to wake the two up.

By a glance you could tell Riku was adopted, he looked different from his family, with his slightly tan skin and fiery red hair, the only quality that made him fit in with his new family, was his red eyes. His aunt, now mother, also had them.

His older siblings, Yui and Daichi inherited their mothers blonde hair and red eyes, while the twins had black hair and blue eyes like his uncle. Rikus dad and his uncle looked nothing alike, as his dad had red hair and pink eyes. Just like his siblings, each of them inherited traits from only one of the grandparents.

Everyone in the Nanase household knew about the adoption, but they didn't care at all, they grew up together for 4 years now, even though they aren't siblings by blood, they're still cousins.

"Abe! Natsu! Wake up." Riku said as he opened the door to the twins room. The twins opened their eyes to their brother's face right in front of them. "Get up or you'll be late"

They were confused for a short while, their brother moved out a few weeks ago, but now he was waking them up like usual. It took a few seconds for them to process this.

The two of them finally got up and Riku went back to the kitchen, sitting down at his chair at the table.

Finally, his mother came into the kitchen with plates, and as she put them down on the table, she remembered something.

"Riku, Yui told me you met Tenn-kun yesterday. Are you alright?" Concern filled her voice, she knew that Riku wasn't fond of Tenn. Hatred would be the right word to describe his situation.

"I'm alright, mom. We aren't family anymore with Tenn, he's just an idol from a rival group now." Riku said as he beamed his iconic smile.

The rest of the morning went by fast. After they ate breakfast, Riku walked the two boys to school as it wasn't far from the train station and his train was arriving in a while, so he had to go there anyway.

" Riku-nii, when will you come home again?" Natsu, the youngest of the twins, asked.

"probably next week, although I won't stay over." Riku said "I can bring my friends to play with you two too if you want."

"Yeah!" The two boys said loudly with extent.

"Riku-nii, I want a piggyback ride!" the other one yelled while he raised his hands towards the red head.

"Alright, but not for long, you know about my condition." he said while stopping and bending down to pick up one off the twins and put him on his shoulders. The twins may be 8 years old but they were small, it was prominent that they inherited the short height from their mom.

The other boy took the hand of their brother and walked next to him for the remainder of the way to school.

_**\------** _

After dropping them off Riku went to the train station, where he met up with Mitsuki and Iori. They also visited their home, and since they lived in the same neighborhood, they decided to go back together.

"Your brothers are cute Riku" Mitsuki said mid conversation.

"You saw them? When?" the twins weren't introduced to the rest of idolish7 yet, but here was Mitsuki talking about them.

"Yeah, we saw you walk with them when we were making our way here." Iori replied this time. "Are you sure it was alright for you to carry one on your shoulders."

"It's fine, I did it a lot in the past and it wasn't that long." Riku replied. "They're my pride, I never had younger siblings before them, only older ones. I'm a big brother finally."

"I know your feelings Riku, Iori was so cute as a child, I really don't know how he became like this." Mitsuki said with a sigh. "But don't misunderstand Iori, you're still my cute little brother."

"It's alright Nii-san" Iori replied, but his emotions were a bit hurt by the earlier statement.

"Ah, the train is here" Riku said as he heard the announcement of the train arriving. "Let's go."

_**\------** _

**Author's Note:**

> I'm sorry Tenn !
> 
> I hate/love Tenn, I want to make him suffer a bit, since he's happy in my other 2 fics. (One is still not published)  
> Thank you for reading !


End file.
